=====================================================
BUG: KMSAN: uninit-value in __gre_xmit net/ipv4/ip_gre.c:469 [inline]
BUG: KMSAN: uninit-value in ipgre_xmit+0xdc2/0xe20 net/ipv4/ip_gre.c:662
 __gre_xmit net/ipv4/ip_gre.c:469 [inline]
 ipgre_xmit+0xdc2/0xe20 net/ipv4/ip_gre.c:662
 __netdev_start_xmit include/linux/netdevice.h:4918 [inline]
 netdev_start_xmit include/linux/netdevice.h:4932 [inline]
 xmit_one net/core/dev.c:3543 [inline]
 dev_hard_start_xmit+0x247/0xa10 net/core/dev.c:3559
 __dev_queue_xmit+0x33b8/0x5130 net/core/dev.c:4344
 dev_queue_xmit include/linux/netdevice.h:3112 [inline]
 packet_xmit+0x9c/0x6b0 net/packet/af_packet.c:276
 packet_snd net/packet/af_packet.c:3087 [inline]
 packet_sendmsg+0x8b1d/0x9f30 net/packet/af_packet.c:3119
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
 __sys_sendmmsg+0x4e2/0x950 net/socket.c:2717
 __compat_sys_sendmmsg net/compat.c:360 [inline]
 __do_compat_sys_sendmmsg net/compat.c:367 [inline]
 __se_compat_sys_sendmmsg net/compat.c:364 [inline]
 __ia32_compat_sys_sendmmsg+0xc8/0x140 net/compat.c:364
 do_syscall_32_irqs_on arch/x86/entry/common.c:164 [inline]
 __do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:230
 do_fast_syscall_32+0x37/0x70 arch/x86/entry/common.c:255
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:293
 entry_SYSENTER_compat_after_hwframe+0x70/0x7a

Uninit was created at:
 slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768
 slab_alloc_node mm/slub.c:3478 [inline]
 kmem_cache_alloc_node+0x5e9/0xb10 mm/slub.c:3523
 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:560
 pskb_expand_head+0x226/0x1a00 net/core/skbuff.c:2098
 __skb_cow include/linux/skbuff.h:3586 [inline]
 skb_cow_head include/linux/skbuff.h:3620 [inline]
 ipgre_xmit+0x74a/0xe20 net/ipv4/ip_gre.c:638
 __netdev_start_xmit include/linux/netdevice.h:4918 [inline]
 netdev_start_xmit include/linux/netdevice.h:4932 [inline]
 xmit_one net/core/dev.c:3543 [inline]
 dev_hard_start_xmit+0x247/0xa10 net/core/dev.c:3559
 __dev_queue_xmit+0x33b8/0x5130 net/core/dev.c:4344
 dev_queue_xmit include/linux/netdevice.h:3112 [inline]
 packet_xmit+0x9c/0x6b0 net/packet/af_packet.c:276
 packet_snd net/packet/af_packet.c:3087 [inline]
 packet_sendmsg+0x8b1d/0x9f30 net/packet/af_packet.c:3119
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
 __sys_sendmmsg+0x4e2/0x950 net/socket.c:2717
 __compat_sys_sendmmsg net/compat.c:360 [inline]
 __do_compat_sys_sendmmsg net/compat.c:367 [inline]
 __se_compat_sys_sendmmsg net/compat.c:364 [inline]
 __ia32_compat_sys_sendmmsg+0xc8/0x140 net/compat.c:364
 do_syscall_32_irqs_on arch/x86/entry/common.c:164 [inline]
 __do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:230
 do_fast_syscall_32+0x37/0x70 arch/x86/entry/common.c:255
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:293
 entry_SYSENTER_compat_after_hwframe+0x70/0x7a

CPU: 0 PID: 6841 Comm: syz-executor.1 Not tainted 6.6.0-syzkaller-16159-g3ca112b71f35 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
=====================================================